Migratory monarch butterflies have historically followed specific flight paths across generations, which led entomologists to hypothesize that a related species, the Southern Viceroy, might display similar rigid migratory patterns. Viceroy wings develop in stages, trapping chemical signatures from the vegetation they consume as larvae; thus, the chemical composition of the wings indicates where the butterfly lived as a caterpillar. Recent chemical analysis of Southern Viceroy wings compared to the chemical distribution of local flora shows that the butterflies’ range expands significantly during wet seasons, only to shrink drastically during dry spells.
Which choice best describes the function of the underlined statement in the text as a whole?
It describes a biological similarity between two species to explain why scientists proposed a theory that is later challenged by new data.
It outlines a proven fact about butterflies to support a new theory that is confirmed by the study mentioned later in the text.
It introduces a chemical process to explain how researchers determined the age of the butterflies mentioned later.
It presents a behavior of Monarchs to argue that Viceroys are actually the same species.
Correct Answer: A
Choice A is the best answer. The underlined sentence introduces the behavior of Monarchs (fixed flight paths) to explain why researchers speculated the Viceroy would do the same. The text later shows the Viceroy actually expands and contracts its range, which contradicts that speculation.
Choice B is incorrect. The study complicates the theory rather than confirming it. Choice C is incorrect. The underlined part discusses migration, not the chemical process (discussed later). Choice D is incorrect. The text compares behaviors, not species classification.